1. Field
Aspects of the present invention generally relate to a breaker handle block and unblock mechanism of a circuit breaker and more specifically relates to a locking mechanism for blocking and unblocking a breaker handle of a multi-pole electronic circuit breaker.
2. Description of the Related Art
Electrical circuit branches of single-phase AC power systems typically use electrical cables that include a line conductor and a neutral conductor coupled between a source and a load, with the neutral conductor grounded at the source. Ground fault circuit interrupt (“GFCI”) devices are installed in such circuit branches to interrupt power upon detection of ground current faults from the line conductor to ground at the load, as well as grounded neutral faults (e.g., low impedance connection faults) between the neutral conductor and ground at the load. Electrical arcs can develop temperatures well above the ignition level of most common flammable materials and, therefore, pose a significant fire hazard. Two types of dangerous arcing that are likely to occur in the home are momentary, high-energy arcs caused by high-current faults and persistent, low-current “contact” arcing. As such, the maximum current in the arc is limited to the load current and, therefore, may be substantially below the over-current or “trip” rating of an associated circuit breaker. Arc fault circuit interrupt (“AFCI”) devices are used in circuit breakers which are installed to prevent dangerous conditions due to high-energy arcs and contact arcing.
A two-pole circuit breaker is constructed by pairing two single pole circuit interrupters into one construction. The two-pole circuit breaker could be a traditional circuit interrupter or an electronic circuit interrupter that detects ground faults and/or arc faults as well as over current conditions of equipment electrically coupled as a load to the two-pole circuit breaker.
Two-pole residential circuit breakers do not provide a means to block a breaker handle from going to a fully ON position in which the main contacts of the circuit breaker fully close. Thus preventing the main contacts to close. This is important in the event of two conditions. One condition is if the arc or ground fault circuitry is no longer able to detect a fault condition. The second condition is if a fault condition is present when the circuit breaker is turned to the fully ON position. In both cases, the breaker handles today can be rotated to the fully ON position and the main contacts close.
Therefore, there is a need for improvements to preventing the main contacts of a circuit breaker to close for preventing a dangerous situation involving a fault condition.